When George Shultz was secretary of state in the 1980s, he liked to carve out one hour each week for quiet reflection. He sat down in his office with a pad of paper and pen, closed the door and told his secretary to interrupt him only if one of two people called:

“My wife or the president,” Shultz recalled.

Shultz, who’s now 96, told me that his hour of solitude was the only way he could find time to think about the strategic aspects of his job. Otherwise, he would be constantly pulled into moment-to-moment tactical issues, never able to focus on larger questions of the national interest. And the only way to do great work, in any field, is to find time to consider the larger questions.

This is especially interesting to me because I’m working now on a sequel of sorts to REST, a project that looks at how companies today are finding ways of shortening working hours (like the famous Swedish experiments), moving to a 4-day workweek, and experimenting with other way to help people get their work done and have more time to themselves– free time without email or unfinished projects hanging over them.

One of the reasons it’s possible to shorten the work day is that the conventional workday is awfully inefficient: surveys over the past decade have estimated that between 25% and 50% of knowledge workers’ days are spent dealing with information overload, email deluges, being interrupted, or recovering from distractions. (I’ll leave the specific citations for another post.) So there’s a lot of slack in the system that can be taken up, without a big hit on productivity.

But one of the things that people worry about when they shift from a conventional workday is that they intuit that a certain amount of “unproductive” time can be quite valuable, and can provide either a break from work or a chance to explore new ideas. The problem is that most of these wasted hours are genuinely wasted: checking your Zappos order in the middle of a two-hour meeting isn’t going to lead to a company-transforming insight.

Instead, you have to build in time for breaks, be they regular walks, naps, or Shultz hours. Scheduling them means that you can control when in the day they fall, and thus improve the odds that they’ll yield something useful. Scheduling them also means that you’ll actually take them: in a super-busy job like secretary of state, it’s very easy to never have any time to yourself. Finally, there’s plenty of evidence that practice helps you enter creative states, and that scheduling them both gives you practice, and gives your creative mind a regular time to stretch itself.